1. Field of the Invention
The present invention relates generally to air bearing sliders and more particularly to the establishment of a positive crown and camber on the slider utilizing deposited thin films.
2. Description of the Prior Art
Air bearing sliders are generally used as mounting platforms for read/write heads for hard disk drives. To optimize the read/write head performance it is necessary to carefully control the height of the read/write head, and to do so, it is necessary to control the height at which the slider flies above the hard disk surface. Generally, the closer that the read/write head flies to the surface of the hard disk, the better performance characteristics are obtained.
Typically, the read/write head is disposed at the rearward edge of the slider, and the optimal slider flying orientation is such that the rearward edge flies closest to the disk surface, whereas the leading edge of the slider flies higher off of the disk surface. Improved slider flying characteristics have been obtained in the prior art by providing a positive crown and camber to the air bearing surface (ABS) side of the slider. Positive crown refers to a generally convex arc of the ABS side from the leading edge to the trailing edge, while positive camber refers to a generally convex arc from the left edge to the right edge of the ABS side.
Various devices and methods have been developed in the prior art to achieve positive crown and camber. Such methods include the physical shaping of the surfaces, such as by lapping, as well as devices that are designed to provide adjustable crown and camber. Such adjustable devices include piezoelectric elements in the slider structure which respond to electrical current from a control system to physically alter the shape of the slider to achieve positive crown and camber. Such a device is described in U.S. Pat. No. 5,021,906, issued Jun. 4, 1991 to Chang, et al.
Another prior art method for achieving positive crown and camber involves the use of a backing material having a higher thermal expansion coefficient than that of the slider body material. The backing material is deposited by high temperature sputtering on the flexure side of the slider. When the temperature of the processed slider returns to room temperature, the difference in the thermal expansion coefficients between the backing material layer and the slider body material causes a positive crown and camber to occur. This slider manufacturing method is described in Japanese Patent No. 1,030,082, entitled: Manufacture of Magnetic Head Slider, issued Jan. 31, 1989 to Daito et al.
A simplified method for achieving positive crown and camber is desirable in the industry. For many applications it is sufficient to utilize a slider that is permanently formed with a positive crown and camber, as opposed to the complexity of a slider having an adjustable crown and camber, which requires additional control systems. Additionally, where slider materials are temperature sensitive, the utilization of high temperature sputtering to take advantage of differing thermal expansion coefficients is not desirable. A need therefore exists for a simple and effective method for achieving positive slider crown and camber. The present invention seeks to fill that need by utilizing thin films having compressive force or tensile force properties that achieve positive crown and camber when deposited upon the appropriate surfaces of the slider.
An air bearing slider embodiment of the present invention includes a body portion having an air bearing surface (ABS) side and a flexure surface side. The ABS side has at least one air bearing surface and at least one recessed area. A thin film composed of a compressive force material is deposited within the recessed area. The compressive force material produces an omnidirectional outward force within the recessed area that creates a positive crown and camber. Preferably, the thin film has a thickness range from 10 nm to 200 nm, and is composed of diamond-like carbon (DLC). An alternative air bearing slider includes a body portion with an ABS side and a flexure surface side. A thin film composed of a tensile force material is deposited upon said flexure side. The tensile force material creates an onmidirectional inward force on the flexure side which results in positive crown and camber. The manufacturing method for the improved sliders utilizes semiconductor processing techniques. The basic slider body is appropriately masked and etched to create the air bearing surfaces, air pressure surfaces and recessed area of the ABS side. Thereafter, the compressive material thin film is deposited within the recessed area. An improved manufacturing method utilizes the preexisting photomask of a prior art slider design, such that additional photomasking steps are not required to achieve the deposition of the compressive material thin film. Manufacturing of the tensile force material embodiment requires the step of depositing the film upon the flexure side.
It is an advantage of the present invention that a slider having improved positive crown and camber is produced.
It is another advantage of the present invention that a slider having improved positive crown and camber is produced utilizing existing manufacturing steps with the addition of a thin film deposition step.
It is a further advantage of the present invention that an improved slider is produced with minimal increased cost and complexity to the slider manufacturing process.
These and other features and advantages of the present invention will become well understood by those skilled in the art upon reviewing the following detailed description which makes reference to the several figures of the drawing.